This invention relates to a lock which is suitable for use as a door lock. It is to be understood however that the scope of the invention is not confined to this particular application.
A door lock which is in widespread use has a bolt which is movable between locked and unlocked positions. The bolt is movable by means of a key which is manually rotatable and which acts on one or more lock levers which have formations which match complementary formations on the key. A catch, which forms part of the lock, is movable by means of a handle so that a door, to which the lock is mounted, can be moved from a closed position to an opened position.
Electrically operated locks have been proposed wherein the movement of the bolt is effected by means an electrical device such as a solenoid or motor. The solenoid is actuated by means of a security mechanism such as a keypad and draws power from a mains or battery supply in order to move the bolt.
The provision of power to a lock of this type may pose some problems.
Firstly if use is made of power drawn from a mains supply then one is faced with the difficulty of leading electrical conductors to the lock. On the other hand if use is made of an onboard power supply such as one or more batteries then the current drain on the batteries may be such that the batteries must be replaced at regular intervals of relatively short duration. This problem becomes pronounced under certain conditions for example when friction forces are generated, which impede the movement of the lock components.
The invention provides a lock which includes a bolt which is movable between a locked position and an unlocked position, first retaining means which is engaged with the bolt and which retains the bolt in the locked position, remotely actuable release means for moving the first retaining means out of engagement with the bolt, and handle means for moving the bolt from the locked position to the unlocked position when the first retaining means is disengaged from the bolt.
The bolt is movable from the locked position to the unlocked position against the action of a biassing element such as a spring. Energy accumulated in the biassing element may be used for subsequently returning the bolt to the locked position. This eliminates the need for an external energy source to operate the lock; for example electrical energy required to drive an electric motor to move the bolt. The handle is operated by a person opening the door. Thus the energy to bias the biassing element is supplied by the user.
Preferably the first retaining means is movable between a first position at which the first retaining means restrains the bolt from being moved from the locked position to the unlocked position and a second position at which the first retaining means restrains the bolt from being moved from the unlocked position to the locked position, and the release means, when actuated, causes movement of the first retaining means from the first position to the second position.
The lock may include biassing means which is biassed when the bolt is moved to the unlocked position. The biassing means may provide energy for restoring the bolt to the locked position.
The release means may be electrically actuable. The release means may take on any suitable form and for example may include an electric motor.
The release means may be responsive to a signal which is output by a receiver and decoder unit which, in turn, is responsive to an externally generated signal for causing operation of the lock.
Preferably the lock includes energy storage means which accumulates energy as the bolt is moved to the unlocked position, second retaining means, engageable with the bolt, for retaining the bolt in the unlocked position, and means for disengaging the second retaining means from the bolt whereupon the energy storage means causes the bolt to be moved to the locked position.
The first and second retaining means may be formed by inter-engageable formations respectively on the bolt and on at least one lever.
The first retaining means may be movable in any appropriate way and, for example, use may be made of a cam, a gear mechanism e.g. a worm gear arrangement, which acts on the cam, and an electrical motor which drives the gear mechanism, and hence the cam, in a controlled manner.
The first and the second retaining means may also be movable by means of a key of any appropriate type. This enables the bolt to be manually locked or unlocked according to requirement.
The lock may include a receiver and decoder which receives an externally generated signal from any appropriate source such as a card reader, keypad, any suitable recognition device, a switch device, a radio transmitter or the like. The scope of the invention is not limited in this regard. If a correctly encoded signal or a valid signal is received then the retaining means may be moved in the manner described.
Communication with the lock may be unidirectional, or bidirectional e.g. in a xe2x80x9cchallenge-responsexe2x80x9d routine or mode. In each case a signal may be transmitted, by a direct link or a wireless link, from a source which is close to a lock, or from a remote source e.g. a central control point. The signal could simultaneously actuate a number of locks. A phone link, an Internet connection, or any similar device or arrangement could be used to address the lock directly or through the medium of a control unit. The lock may be capable of reporting or responding, e.g. to a control unit or any actuating source, through any appropriate medium, directly or through a wireless, Internet or other link. The lock may for example report to an alarm system to indicate that a door is open or closed or, possibly, that the door has been forced open.
Where a plurality of locks are used, a central system or an alarm system may be installed that can individually or collectively instruct the locks to lock and unlock. The locks may report to the central system indicating information such as whether they have been successfully locked, and whether the respective doors are open or closed. The central system may also communicate with other systems which may include garage doors to lock and unlock such doors and to check on their status such as open or closed. The central system may be interfaced by a user directly or may be communicated with by the user via a telephone link, the Internet or a satellite. This communication may take place via a variety of mediums, such as wired, radio frequency and infrared links.
Single hand held controllers may be used to lock a variety of locks with one button press, or single locks with the press of another button, or a code of button presses. For certain buttons of the hand held controller, the power that is emitted may be higher than for other buttons of the same hand held controller. This makes it possible to limit the working range of some of the buttons on the hand held controller and helps to prevent the accidental locking and unlocking of surrounding locks if a specific lock is to be locked and unlocked, if a hand held controller can lock and unlock more than one lock. For hand held controllers communication can take place via a variety of mediums, such as radio frequency and infrared links.
It is also possible to actuate the lock by means of any appropriate device, e.g. a push button, which is installed at a convenient and safe location and which may be linked directly to the lock.
The lock may include an energy storage device such as at least one battery. The battery may be stored in a housing in which mechanical components of the lock are mounted or in a separate easily accessible housing.
The lock may include cam means which acts on the first retaining means, an electrically driven gear mechanism, which is remotely controllable, for causing controlled movement of the first retaining means from the said first position to the said second position, energy storage means which accumulates energy as the bolt is moved, and means for preventing movement of the cam means at least in one direction when the bolt is moved to the unlocked position.
The energy storage means may provide energy for restoring the bolt to the locked position. Alternatively, if energy is stored when the bolt is moved to the locked position, the energy storage means is used to restore the bolt to the unlocked position.
The electrically driven gear mechanism may include an electric motor which drives a gear arrangement such as a worm gear and preferably is responsive to a signal which is output by a receiver and decoder unit which, in turn, is responsive to an externally generated signal for causing operation of the mechanism.
The first retaining means may include at least one lever which is engageable with a stop formation on the bolt.
A sensor of any appropriate type e.g. optical, magnetic, inductive etc. may detect whether a door, to which the lock is fitted, is open or closed and only allow actuation of the bolt in a manner which depends on the door position, e.g. to move the bolt to a locked position only when the door is closed.
The lever or levers may be actuated manually, for example directly by means of a key which acts on the lever or levers, or indirectly by means of a key which acts on a cylinder which, in turn, acts on lever or levers, or in any other way.
Preferably the lock includes a device which is movable between a first position at which, upon operation of the handle, the bolt is caused to move to the unlocked position, and a second position at which, upon operation of the handle, no movement of the bolt results. The said device may for example be a spring or a catch.
The invention also provides a method of operating a lock which includes at least a locking bolt, the method including the steps of storing energy when the bolt is moved manually in a first direction, latching the bolt at a first position using retaining means, transmitting a signal to actuate the retaining means to unlatch the bolt, and allowing the locking means to move in a second direction opposite the first direction under the action of the stored energy.
The transmitted signal may be transmitted from a remote point using an electronic key eg, suitable wireless means, or a connection which is made directly to the retaining means or an actuator thereof.
It fails within the scope of the invention to actuate the lock electronically or by means of a mechanical key. By making use of a transmitter which can transmit more than one signal it is possible to control the operation of the lock in a variety of ways, according to requirement. For example the operation or potential operation of a mechanical key can be disabled electronically to enhance the security of the lock. Thus, by way of example, the aforementioned cam means may include a cam surface which actuates one or more members which prevent direct or indirect engagement of a mechanical key with the bolt or with a device which causes bolt movement.